screacher!screacher!Manic Freak

Manic Freak schuMacher’s

Twin-engined schuMacher’s

Twin-engined

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By StEvE BASS

SChuMAChER 1:8 4WD tWIn-EngInE ‘MAnIC’ MOnStER

screacher!

AnD nOW FOR SOMEthIng…

Every once in a while those nice sensible people at

Schumacher prod an elbow into the ribs of the world’s R/C

car community by producing something that is not only

completely different, but invariably proves to be a whole

load of fun. This time however, it looks like they really have

thrown the rulebook out of the window!

For starters, this baby is big, and weighs in at over 4 kg,

which is what you would expect from a 1:8 scale monster

truck! Of course it must have four wheel drive to give it that

all-important ‘go anywhere’ ability and it must have huge

wheels and tyres to provide the necessary ground clearance

and traction that you will want to tackle any type of terrain.

I will take you through all the other ingredients of the

Manic as I tear it apart and subject it to the usual RRCi

autopsy, but before that we need to take a look at what

makes this crazy machine stand out from the crowd… and

that is the power plant.

…COMPLEtELy DIFFEREnt

If you haven’t already guessed, the Manic is powered by a twin

cylinder 0.36 (6 cc) nitro fuelled engine package, that promises

double the horsepower and double the torque of a conventional

big block engine, but without the added hassle that can sometimes

afflict a twin-engined machine, and it has certainly generated a

huge amount of interest around the world, most of which revolved

around that engine. Photographs of the Manic did nothing to give

the game away. The distinctive twin heatsink head was clearly

visible, but the bit that everyone wanted to see was not!

Now we can put an end to the mystery and RRCi will reveal all!

However, let’s first take a tour of all the other key construction

details of this crazy machine.

Main pic: On the loose the 4WD system

comes into its own.

Remember to oil your air filter first!

SPEC ChECK

MODEL tyPE: 4WD,

OFF-ROAD, LEISuRE

LEngth: 460 MM

WIDth: 400 MM

WEIght: 4 Kg POWER

SOuRCE: .36 (6 CC)

tWIn CyLInDER nItRO EngInE

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ROLLIng ChASSIS LAyOutIf you are familiar with the Schumacher Havoc, then you will soon

start to recognise a number of common parts that have been carried over to the Manic. The 6082 purple T6 alloy chassis is totally flat, with black composite bumpers attached front and rear. Although you do not get a choice of shock mounting positions, both shock towers are really substantial mouldings. The purple alloy shocks are conventional enough, featuring twin foam volume compensators in each, and providing a huge 70 mm of travel. Their extreme lay-down positioning (the lower mounts are on the hubs!) help to give the Manic its low profile silhouette. You get four pairs of adjustable turnbuckles all round, enabling front/rear toe and camber adjustment.

The front and rear wishbones are actively mounted to the chassis, and like the rest of the mouldings on this machine, they are big and beefy, and should shrug off the inevitable punishment that extreme off road terrain can deal up. The wishbones sit flush with the underside of the chassis providing huge axle articulation, but obviously without any droop adjustment.

The composite construction radio tray houses the stand-up steering and throttle/brake servos. The steering servo delivers 9.7 kg/cm of torque with a 60° lock-to-lock sweep in 0.12 seconds if using a 5-cell (6 V) receiver battery. The steering arrangement consists of twin chassis mounted posts, with upper and lower turnbuckle drag links. The left-hand post features an adjustable servo saver with the adjusting collar

located at the top of the post assembly, making access for adjustment very simple. Moving along the radio tray, the receiver box is found behind the two servos, and this is wired in stadium truck fashion to a battery box at the rear, just behind the rear axle centre line. An ON/OFF switch is also located on the radio tray, and this can be easily operated with the bodyshell attached. For general maintenance the Manic proved to be about as difficult as falling off a log! The radio tray for example is out of the chassis with just three screws, making it a breeze to clean when you’ve finished playing.

The 125 cc fuel tank is attached to the left of the chassis just ahead of the engine so refuelling can be done with the bodyshell attached, and if you wish, you can fit a lid puller to the tank to make the job a little easier. Twin exhaust manifolds are integrated with the single exhaust can and rear facing stinger pipe.

Above: Those massive wheels jack the gearing and ground clearance up

Above: Rear mounted battery box and laydown shocksRight: Nitro Starter Kit includes a fuel bottle, basic tools and a glow start, though you’ll be needing another…

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Finally, the chassis rolls on ‘super grip’ tyres and huge chrome-effect wheels, which are attached by 17 mm hex nuts. Using 17 mm hubs opens up a world of choice when it comes to future wheel and tyre options. Unfortunately Schumacher do not include a wheel nut wrench, which is why it is a good idea to consider buying the very reasonably priced Nitro Starter Kit, which resolves this problem and also gives you a box spanner, fuel bottle, glow starter (although it’s far better to use two glow sticks to start the Manic!) and a couple of crosshead and flat blade screwdrivers.

tRAnSMISSIOnDrive is transmitted from the twin shoe clutch (how many times have I

said ‘twin’) to a 24 DP spur gear. The clutch is rather like the popular MIP hop up, but be careful when removing the clutch bell as it runs on floating needle rollers with no cage to keep them together. The spur gear layshaft is the first part of a triple metal gear reduction box with a ball differential whose unequal length outdrives transmit drive to the rear wheels via a pair of really chunky telescopic driveshafts. On the outer end of the spur gear top layshaft a pulley and toothed belt drive connects to the input shaft for the front gearbox, which follows the same method of reduction and drive to the front wheels, as it does at the rear. The chunky square section telescopic driveshafts feature CV joint stub axles, each of which attaches to the aforementioned 17 mm hex hub. The entire transmission and wheel hubs are fully ball raced with sealed bearings.

Working on the Manic is a breeze. The front and rear transmission assemblies can be split from the chassis with the removal of just four or five screws and popping a few ball joints. It couldn’t be easier. The same goes for drive belt replacement, which is even easier. Remove one of the belt pulleys and the rear radio tray post and you can swap the belt in just a few seconds.

tWO hEADS BEttER thAn OnE?And so we arrive at perhaps the most interesting aspect of the Manic!

With a total displacement of 6 cc it is in fact a pair of 3 cc (.18 ci) engines that have been paired up with operationally linked crankshafts. This latter item is crucial to the smooth running of the engine, and is why the Manic power plant should function without any of the problems that can afflict other twin-engine applications. The engines always drive each other reducing the risk of a low tick-over flame out, and allowing a taller overall gear ratio than either could pull alone.

The rearward of the two engines is the one that is connected directly to the transmission and the first thing mounted on the external crankshaft is a toothed belt drive pulley, followed by the conventional flywheel, clutch and clutch bell assembly. A special flywheel on the forward engine also accommodates the same type pulley, and it is the toothed belt drive between the two engines that keeps everything synchronised.

Now that you know what literally makes this twin-engine ‘tick’ let’s look

Above: Adjustable servo saver and front disc brake assemblies

Above: Chunky arms and driveshafts are matched by the solid chassis plate which looks bump box compatible, but isn’t

Above: Digital 27 MHz ‘Response’ radio transmitter offers all the essential features, and a few more besides

Above: 4WD transmission layout clearly visible (air filter removed for clarity) shows power being carried forward by the drive belt and pullies

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at the assembly in more detail. As you can see the engines sit on a central mounting plate and a pair of engine posts at the front and rear. So after removing six screws, the whole lump comes out as a single unit. That eye-catching heat sink head is a single piece of billet-machined alloy, and attaches to the two engines in the normal way with four bolts apiece.

The next interesting feature is the purple anodised carburettor inlet manifold. This item provides for the simplicity and reliability of a single carburettor feeding both engines. Access to the top end mixture screw is nice and easy as this sits atop the carburettor pointing skywards. The bottom end screw is forward facing and can be adjusted with a flat blade driver. Adjusting the idle screw is slightly more awkward as it is at an angle close to the heat sink head. The engine breathes through a twin (there’s that word again) stage air filter which you have to lube and fit yourself before first firing it up.

The engine exhausts exit through a pair of unequal length manifolds and a cylindrical transverse silencer can with a single rubber stinger pipe pointing out of the back.

The Manic kit comes with a Rotostart drill attachment, which you can use with any suitable cordless drill, or if you prefer, the optional Schumacher Rotostart electric starter. As I mentioned earlier, remember that you will need two glow starters to get the Manic’s twin cylinders fired up, preferably a long reach Core Glow start (CR046) to clear the truck cab and reach the engine below, while the rear engine can be reached by a regular short glow stick like that included in the Nitro Starter set (G852), as the load deck sits only just above the heat sink.

So that is what makes the Manic go, but what about stopping it? Thankfully the answer is that both front and rear gearboxes are braked separately, so with no centre diff the two brakes work together and pull the truck down from extreme speeds without a fuss, even with just a 4-cell receiver pack.

EngInE AutOPSyIf you are familiar with Schumacher products, you will also know about

their liking for Torx fasteners and whilst you get a basic Allen and Torx key set included, it’s worth buying yourself a Torx driver and bit set, before starting any work on the Manic, but bear in mind that Schumacher have their own T10 Torx driver (HW008) though it’s not always included in the kits.

The easiest way to remove the engine is complete with its engine mount, which, as I mentioned earlier, involves removing the six chassis screws. The exhaust can is stabilised with a mounting wire retained by a setscrew, but we found it necessary to remove the complete mounting wire because the exhaust fouled on the rear brake pivot, preventing its removal. On closer inspection we found that on our Manic we could remove about 5 mm off the mounting wire with a Dremel, which would then give sufficient room to remove the engine and exhaust quicker and easier. Obviously you also have to disconnect the throttle return spring and throttle linkage and fuel pipe connections and in about one minute, the whole lot is on the bench.

If you wish to ‘split’ the engine, you can now see that it’s a case of removing the centre bracket, which locates on the two crankcases at the base, and the one-piece heat sink head. The head bolts were VERY tight on our review Manic, so use a good quality hex driver. Slacken the two pinch bolt nuts that clamp the one-piece inlet manifold and lift off the inlet manifold and single carburettor assembly. You can now remove the two-piece synchro drive cover, which exposes the synchro drive belt. Next, cut the tie wrap retaining the forward exhaust manifold (the twin manifolds and exhaust can are a one-piece item) and pull the forward pipe off the manifold flange. You can now just slip the drive belt off and you have successfully split the engine. To access just the synchro drive belt, the bottom half of the cover slips off easily enough (mind you don’t lose the little strengthening plate that slots in the centre), but to remove

Above: Starter unit is built onto rear engine crank. Two into one exhaust system with rear facing single stinger. Admit it…you want one!

Above: Optional U3544 synchro assembly jigs are used to set the cranks exactly 180 degrees apart for best power deliveryLeft: Twin shoe clutch and loose needle rollers within the bell. Be sure to keep them lubricated

Above: Big end alignment after fitting synchro jigs, means two power pulses per revolutionRight: Synchro drive is normally shrouded by two-piece protective cover. Tightening the drive locknut after synchronising the engines

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the top half you first need to remove the inlet manifold and carburettor.If removing the Rotostart back plate make sure you don’t lose the tiny

crank pin which may drop out into the bowels of the engine! I know a few people that have reassembled these (and similar pull start mechanisms), only to find they don’t work after re-assembly because they missed this vital little crank pin!

Reassembly of the engine is almost, but not quite, the reverse of the strip down! Once you have rebuilt the engine mount, heat sink head, synchro drive belt and exhaust, the engine timing must be set. The manual details clearly how this is done, but the job is a lot easier if you purchase the optional synchro assembly jigs (U3544). Basically, these are a pair of back plates that temporarily replace the rear engine Rotostart assembly and the forward engine’s standard back plate, which ensures the engines are ‘synchronised’. To do this, you first need to slacken the belt pulley locknut.

The forward engine has a conventional back plate, whilst the rearward engine has the Rotostart assembly and cover plate. With both of these items removed, and the aforementioned belt pulley locknut slackened off, you rotate the cranks so that the con rod big ends are correctly positioned. They must be diagonally opposite each other, halfway between TDC and BDC, so that one cylinder is on the ‘up’ stroke and the other on the ‘down’ stroke. The next step is to fit the timing jigs where the back plate and Rotostart would normally be fitted. This ensures that the crank in each engine is precisely in the correct position. After this it is just a case of tightening the locknut, removing the timing jigs and re-assembling the Rotostart and forward engine back plate.

tOPPIng OFFThe Manic is topped off with good quality lexan pre-painted shell,

available in a choice of two colour schemes. These are 99% finished but Schumacher includes a decal sheet for the front and rear lights, radiator grille and you own personalisation. The shell is pre-cut with twin (there I

go again) glow starter holes, and a side access hole for the starter. As it does not have a conventional flywheel, the Manic cannot be used with a bump start box. However, we had absolutely no problem cranking it up with Schumacher’s optional mini roto starter.

RADIOYour Manic comes with a rather nice ‘Response’ branded 3-channel

digital (steer wheel) radio transmitter, operating on 27 MHz FM. It is a nicely balanced piece of kit, ready for you to install the eight AA size batteries. An external charging jack is built in if you prefer to use NiMH rechargeable AA cells, although you do not get a mains charger with the kit. You get all the essential ingredients, plus a few surprises. External buttons provide access to steering and throttle trim, throttle ATL and steering dual rate control. A slide switch powers the unit ON and OFF, and above this is a pair of edit keys for changing values within the software menus, plus a channel selection button and a ‘select’ button for navigating your way around the simple menu options.

Once set-up, your data is stored in a memory chip so you won’t lose it should the batteries run flat. In any event, an audible alarm will warn you when the transmitter voltage drops below 8.5 V, although in truth, you shouldn’t let it drop below 9 V. The voltage is displayed on the main LCD when the unit is switched on, along with the model number selected. The transmitter has a 10-model memory and you can assign up to three characters to describe each model. Suffice to say you have a good basic range of programming functions including steering and throttle trim, EPA and exponential, servo reverse and even an ABS menu with three rates of pulse speed.

In use the transmitter has a nicely weighted (right-hand) steer wheel with rubber grip, a longish travel throttle trigger with a relatively short forward movement when braking. All in all, we were very happy with its specification and performance.

Above: Both ball raced gearboxes feature three metal-geared reduction and a Schumacher trademark, the ball differentialAbove left: Synchronicity! Piston 1 at TDC with No 2 at BDCFar left: Twin heat sink is a work of art! Removable head buttons and no less than six shimsLeft: Direct drive rear transmission assembly and drive belt pulley to take power to the front gearbox

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‘MADE tO BE DRIvEn MAD’Because the Manic is so different, a whole host of things were running

through my mind prior to the break-in and track test. Will it live up to expectations? How good is that belt drive? Will the diffs be up to the task? How easy will it be to start? What will it sound like? How easy will it be to tune? Will the rear engine run hotter than the front engine? How good are those brakes? How long will the run times be? All these questions and more would soon be answered!

First of all I had to run the engine in, and I decided to do this in the pits at a local club meeting, as I didn’t want to push my neighbour’s patience too far! Despite there being about twenty rallycross engines warming up in the paddock at the same time, as soon as the Manic’s .36 twin fired up, I saw a lot of people looking my way, and before long a small crowd had gathered around. That’s how distinctive the engine note is! You get

a starter rod included in the kit and this is destined for use in a cordless drill, but a cordless drill is built for torque and not speed, so even though my drill has a reverse switch so it rotates the right direction, 700 rpm just isn’t fast enough to get the engines fired up, so we had to go with the optional roto start (G857) from Schumacher. Eight tanks later it was ready to really let rip for our thrash test and photo shoot!

The venue for our test was a local skateboard and BMX park, and on the loose the 4WD system comes into its own while the 27 MHz digital radio offers up to 130 metres range, further than the eye can reasonably see. The throttle response was lacking that connected feeling, with a slight delay between command and reaction, so we swapped the 4-cell receiver pack of AA cells for a regular 5-cell, a 1600 mAh NiMH hump pack which improved the steering response and throttle control at a stroke. The throttle return spring

was over riding the throttle servo on just four cells but it was far more drivable with the 6 V battery pack installed and the steering response improvement was another bonus. The jumps and berms provided ample opportunities to stretch the Manic and entertain ourselves, and despite the open belt drive system we had no problems with grit ingress to the pulleys. We ran for between 5 and 10 minutes per tank of fuel at a time depending on the terrain and driving style. After four tanks of fuel we left the Manic to cool down and checked the receiver battery before continuing. Our 5-cell receiver hump pack took just 500 mAh to recharge so we should be easily looking at over an hour of fun time from each recharge.

Running the bottom end slightly lean (1 ½ turns out) while the top end runs slightly rich (3 or 4 turns out) means the tick-over is stable and the engine cools as you use the throttle. Tick-over is misleading and sounds too high so you try to turn it down and the engine cuts repeatedly, so just get the engine up to working temperature around 240F and then adjust the tick-over so it is just about to try and creep forward. Remember it will sound too fast as you are listening to a parallel twin that fires twice per rev and you might be more used to listening to a single cylinder. While the engines are relatively new they will run hot and I found that using the transmitter’s EPA settings to limit throttle movement to about half carb opening improved throttle response and extended the run times without limiting the power on tap. When you have run the first gallon through your engines you will feel them start to loosen up and run slightly cooler so you can tweak the carb slightly for more power and use more full throttle applications. By this time you might be justified in changing the glow plugs for a brand new pair (G69124), as new engines wear and deposit material into the coils and the plugs never work as well as a new pair and any malfunction of a glow plug could prove misleading when it comes to fine carb tuning.

OuR vERDICtYou must judge the Manic for yourself, for it is totally unique! If you

like the idea of a super-fast, twin nitro engined, 4WD bonkers monster truck with ‘go anywhere’ ability (who doesn’t?), then there’s no contest, because there’s simply nothing else like it! As the Manic further extends the family tree with lineage back through the Riot and the Rascal among the stable of home grown, British designed machines, we can only wonder, what on earth is Schumacher going to follow that with? I’m sure it’s only a question of time… RRCi

COntACtFor further information, please contact

Schumacher Racing Tel: +44 (0)1604 790770

or visit: www.racing-cars.com

QUICK SPECClass: 1:8th 4WD Twin-Engine MonsterType: RTR Nitro 6 ccManufacturer: SchumacherPrice: £ 549.99 RRP

WhAt yOu gEtRTR 4WD 1:8 Monster Truck6 cc twin cylinder engine27 MHz digital radio Basic toolkitRoto start shaft

WhAt yOu nEED12 x AA batteries for Tx & Rx2 x Glow startersRotostart + 7,2 V battery pack Battery chargerNitro fuel and bottleHand tools

WhAt WE uSEDNitro Starter Set (G852)Rotostart (G857)2100 mAh NiMH AA x12Core long reach glow start (CR046)20% RTR nitro fuel1600 mAh NiMH receiver pack

DISLIKESLack of starting equipmentCirclips on UJ pinsLimited run time on 125 mlThrottle return spring too strong

LIKESUnique engine conceptOne carb, one starterSounds greatGoes wellStops wellStands out from the crowdChunky driveshaftsRobust chassis componentsDirect drive rear, belt drive front

Above: Metal geared ball differentials have chunky unequal length outdrives and telescopic driveshafts

Above: The optional roto start makes the starting procedure so simple and quick. Highly recommended

Left: The long reach Core Glow Start (CR046) is essential to reach the engine below the high roof, whereas a regular short glow stick included in the Nitro Starter set (G852) reached the engine below the load deck

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